Imported Upstream version 3.6.0

Former-commit-id: da6be194a6b1221998fc28233f2503bd61dd9d14

external/rx/Rx/NET/Source/System.Reactive.Windows.Threading/Reactive/Concurrency/CoreDispatcherScheduler.cs

@@ -0,0 +1,239 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#if WINDOWS
+using System.Reactive.Concurrency;
+using System.Reactive.Disposables;
+using System.Runtime.ExceptionServices;
+using System.Threading;
+using Windows.UI.Core;
+using Windows.UI.Xaml;
+
+namespace System.Reactive.Concurrency
+{
+    /// <summary>
+    /// Represents an object that schedules units of work on a Windows.UI.Core.CoreDispatcher.
+    /// </summary>
+    /// <remarks>
+    /// This scheduler type is typically used indirectly through the <see cref="System.Reactive.Linq.DispatcherObservable.ObserveOnDispatcher&lt;TSource&gt;(IObservable&lt;TSource&gt;)"/> and <see cref="System.Reactive.Linq.DispatcherObservable.SubscribeOnDispatcher&lt;TSource&gt;(IObservable&lt;TSource&gt;)"/> methods that use the current Dispatcher.
+    /// </remarks>
+    public sealed class CoreDispatcherScheduler : LocalScheduler, ISchedulerPeriodic
+    {
+        private readonly CoreDispatcher _dispatcher;
+        private readonly CoreDispatcherPriority _priority;
+
+        /// <summary>
+        /// Constructs a CoreDispatcherScheduler that schedules units of work on the given Windows.UI.Core.CoreDispatcher.
+        /// </summary>
+        /// <param name="dispatcher">Dispatcher to schedule work on.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="dispatcher"/> is null.</exception>
+        public CoreDispatcherScheduler(CoreDispatcher dispatcher)
+        {
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            _dispatcher = dispatcher;
+            _priority = CoreDispatcherPriority.Normal;
+        }
+
+        /// <summary>
+        /// Constructs a CoreDispatcherScheduler that schedules units of work on the given Windows.UI.Core.CoreDispatcher with the given priority.
+        /// </summary>
+        /// <param name="dispatcher">Dispatcher to schedule work on.</param>
+        /// <param name="priority">Priority for scheduled units of work.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="dispatcher"/> is null.</exception>
+        public CoreDispatcherScheduler(CoreDispatcher dispatcher, CoreDispatcherPriority priority)
+        {
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            _dispatcher = dispatcher;
+            _priority = priority;
+        }
+
+        /// <summary>
+        /// Gets the scheduler that schedules work on the Windows.UI.Core.CoreDispatcher associated with the current Window.
+        /// </summary>
+        public static CoreDispatcherScheduler Current
+        {
+            get
+            {
+                var window = Window.Current;
+                if (window == null)
+                    throw new InvalidOperationException(Strings_WindowsThreading.NO_WINDOW_CURRENT);
+
+                return new CoreDispatcherScheduler(window.Dispatcher);
+            }
+        }
+
+        /// <summary>
+        /// Gets the Windows.UI.Core.CoreDispatcher associated with the CoreDispatcherScheduler.
+        /// </summary>
+        public CoreDispatcher Dispatcher
+        {
+            get { return _dispatcher; }
+        }
+
+        /// <summary>
+        /// Gets the priority at which work is scheduled.
+        /// </summary>
+        public CoreDispatcherPriority Priority
+        {
+            get { return _priority; }
+        }
+
+        /// <summary>
+        /// Schedules an action to be executed on the dispatcher.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">State passed to the action to be executed.</param>
+        /// <param name="action">Action to be executed.</param>
+        /// <returns>The disposable object used to cancel the scheduled action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is null.</exception>
+        public override IDisposable Schedule<TState>(TState state, Func<IScheduler, TState, IDisposable> action)
+        {
+            if (action == null)
+                throw new ArgumentNullException("action");
+
+            var d = new SingleAssignmentDisposable();
+
+            var res = _dispatcher.RunAsync(_priority, () =>
+            {
+                if (!d.IsDisposed)
+                {
+                    try
+                    {
+                        d.Disposable = action(this, state);
+                    }
+                    catch (Exception ex)
+                    {
+                        //
+                        // Work-around for the behavior of throwing from RunAsync not propagating
+                        // the exception to the Application.UnhandledException event (as of W8RP)
+                        // as our users have come to expect from previous XAML stacks using Rx.
+                        //
+                        // If we wouldn't do this, there'd be an observable behavioral difference
+                        // between scheduling with TimeSpan.Zero or using this overload.
+                        //
+                        // For scheduler implementation guidance rules, see TaskPoolScheduler.cs
+                        // in System.Reactive.PlatformServices\Reactive\Concurrency.
+                        //
+                        var timer = new DispatcherTimer();
+                        timer.Interval = TimeSpan.Zero;
+                        timer.Tick += (o, e) =>
+                        {
+                            timer.Stop();
+                            ExceptionDispatchInfo.Capture(ex).Throw();
+                        };
+
+                        timer.Start();
+                    }
+                }
+            });
+
+            return new CompositeDisposable(
+                d,
+                Disposable.Create(res.Cancel)
+            );
+        }
+
+        /// <summary>
+        /// Schedules an action to be executed after dueTime on the dispatcher, using a Windows.UI.Xaml.DispatcherTimer object.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">State passed to the action to be executed.</param>
+        /// <param name="action">Action to be executed.</param>
+        /// <param name="dueTime">Relative time after which to execute the action.</param>
+        /// <returns>The disposable object used to cancel the scheduled action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is null.</exception>
+        public override IDisposable Schedule<TState>(TState state, TimeSpan dueTime, Func<IScheduler, TState, IDisposable> action)
+        {
+            if (action == null)
+                throw new ArgumentNullException("action");
+
+            var dt = Scheduler.Normalize(dueTime);
+            if (dt.Ticks == 0)
+                return Schedule(state, action);
+
+            var d = new MultipleAssignmentDisposable();
+
+            var timer = new DispatcherTimer();
+
+            timer.Tick += (o, e) =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    try
+                    {
+                        d.Disposable = action(this, state);
+                    }
+                    finally
+                    {
+                        t.Stop();
+                        action = null;
+                    }
+                }
+            };
+
+            timer.Interval = dt;
+            timer.Start();
+
+            d.Disposable = Disposable.Create(() =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    t.Stop();
+                    action = (_, __) => Disposable.Empty;
+                }
+            });
+
+            return d;
+        }
+
+        /// <summary>
+        /// Schedules a periodic piece of work on the dispatcher, using a Windows.UI.Xaml.DispatcherTimer object.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">Initial state passed to the action upon the first iteration.</param>
+        /// <param name="period">Period for running the work periodically.</param>
+        /// <param name="action">Action to be executed, potentially updating the state.</param>
+        /// <returns>The disposable object used to cancel the scheduled recurring action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is null.</exception>
+        /// <exception cref="ArgumentOutOfRangeException"><paramref name="period"/> is less than TimeSpan.Zero.</exception>
+        public IDisposable SchedulePeriodic<TState>(TState state, TimeSpan period, Func<TState, TState> action)
+        {
+            //
+            // According to MSDN documentation, the default is TimeSpan.Zero, so that's definitely valid.
+            // Empirical observation - negative values seem to be normalized to TimeSpan.Zero, but let's not go there.
+            //
+            if (period < TimeSpan.Zero)
+                throw new ArgumentOutOfRangeException("period");
+            if (action == null)
+                throw new ArgumentNullException("action");
+
+            var timer = new DispatcherTimer();
+
+            var state1 = state;
+
+            timer.Tick += (o, e) =>
+            {
+                state1 = action(state1);
+            };
+
+            timer.Interval = period;
+            timer.Start();
+
+            return Disposable.Create(() =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    t.Stop();
+                    action = _ => _;
+                }
+            });
+        }
+    }
+}
+#endif

external/rx/Rx/NET/Source/System.Reactive.Windows.Threading/Reactive/Concurrency/DispatcherScheduler.cs

@@ -0,0 +1,248 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#if !WINDOWS
+using System.Reactive.Disposables;
+using System.Threading;
+
+namespace System.Reactive.Concurrency
+{
+    /// <summary>
+    /// Represents an object that schedules units of work on a <see cref="System.Windows.Threading.Dispatcher"/>.
+    /// </summary>
+    /// <remarks>
+    /// This scheduler type is typically used indirectly through the <see cref="System.Reactive.Linq.DispatcherObservable.ObserveOnDispatcher&lt;TSource&gt;(IObservable&lt;TSource&gt;)"/> and <see cref="System.Reactive.Linq.DispatcherObservable.SubscribeOnDispatcher&lt;TSource&gt;(IObservable&lt;TSource&gt;)"/> methods that use the Dispatcher on the calling thread.
+    /// </remarks>
+    public class DispatcherScheduler : LocalScheduler, ISchedulerPeriodic
+    {
+        /// <summary>
+        /// Gets the scheduler that schedules work on the current <see cref="System.Windows.Threading.Dispatcher"/>.
+        /// </summary>
+        [Obsolete(Constants_WindowsThreading.OBSOLETE_INSTANCE_PROPERTY)]
+        public static DispatcherScheduler Instance
+        {
+            get
+            {
+                return new DispatcherScheduler(
+#if USE_SL_DISPATCHER
+                    System.Windows.Deployment.Current.Dispatcher
+#else
+                    System.Windows.Threading.Dispatcher.CurrentDispatcher
+#endif
+                );
+            }
+        }
+
+        /// <summary>
+        /// Gets the scheduler that schedules work on the <see cref="System.Windows.Threading.Dispatcher"/> for the current thread.
+        /// </summary>
+        public static DispatcherScheduler Current
+        {
+            get
+            {
+#if USE_SL_DISPATCHER
+                return new DispatcherScheduler(System.Windows.Deployment.Current.Dispatcher);
+#else
+                var dispatcher = System.Windows.Threading.Dispatcher.FromThread(Thread.CurrentThread);
+                if (dispatcher == null)
+                    throw new InvalidOperationException(Strings_WindowsThreading.NO_DISPATCHER_CURRENT_THREAD);
+
+                return new DispatcherScheduler(dispatcher);
+#endif
+            }
+        }
+
+        System.Windows.Threading.Dispatcher _dispatcher;
+
+#if HAS_DISPATCHER_PRIORITY
+        System.Windows.Threading.DispatcherPriority _priority;
+#endif
+
+        /// <summary>
+        /// Constructs a DispatcherScheduler that schedules units of work on the given <see cref="System.Windows.Threading.Dispatcher"/>.
+        /// </summary>
+        /// <param name="dispatcher">Dispatcher to schedule work on.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="dispatcher"/> is null.</exception>
+        public DispatcherScheduler(System.Windows.Threading.Dispatcher dispatcher)
+        {
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            _dispatcher = dispatcher;
+#if HAS_DISPATCHER_PRIORITY
+            _priority = Windows.Threading.DispatcherPriority.Normal;
+#endif
+        }
+
+#if HAS_DISPATCHER_PRIORITY
+        /// <summary>
+        /// Constructs a DispatcherScheduler that schedules units of work on the given <see cref="System.Windows.Threading.Dispatcher"/> at the given priority.
+        /// </summary>
+        /// <param name="dispatcher">Dispatcher to schedule work on.</param>
+        /// <param name="priority">Priority at which units of work are scheduled.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="dispatcher"/> is null.</exception>
+        public DispatcherScheduler(System.Windows.Threading.Dispatcher dispatcher, System.Windows.Threading.DispatcherPriority priority)
+        {
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            _dispatcher = dispatcher;
+            _priority = priority;
+        }
+#endif
+
+        /// <summary>
+        /// Gets the <see cref="System.Windows.Threading.Dispatcher"/> associated with the DispatcherScheduler.
+        /// </summary>
+        public System.Windows.Threading.Dispatcher Dispatcher
+        {
+            get { return _dispatcher; }
+        }
+
+#if HAS_DISPATCHER_PRIORITY
+        /// <summary>
+        /// Gets the priority at which work items will be dispatched.
+        /// </summary>
+        public System.Windows.Threading.DispatcherPriority Priority
+        {
+            get { return _priority; }
+        }
+#endif
+
+        /// <summary>
+        /// Schedules an action to be executed on the dispatcher.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">State passed to the action to be executed.</param>
+        /// <param name="action">Action to be executed.</param>
+        /// <returns>The disposable object used to cancel the scheduled action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is null.</exception>
+        public override IDisposable Schedule<TState>(TState state, Func<IScheduler, TState, IDisposable> action)
+        {
+            if (action == null)
+                throw new ArgumentNullException("action");
+
+            var d = new SingleAssignmentDisposable();
+
+            _dispatcher.BeginInvoke(
+                new Action(() =>
+                {
+                    if (!d.IsDisposed)
+                        d.Disposable = action(this, state);
+                })
+#if HAS_DISPATCHER_PRIORITY
+                , _priority
+#endif
+            );
+
+            return d;
+        }
+
+        /// <summary>
+        /// Schedules an action to be executed after dueTime on the dispatcher, using a <see cref="System.Windows.Threading.DispatcherTimer"/> object.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">State passed to the action to be executed.</param>
+        /// <param name="action">Action to be executed.</param>
+        /// <param name="dueTime">Relative time after which to execute the action.</param>
+        /// <returns>The disposable object used to cancel the scheduled action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is null.</exception>
+        public override IDisposable Schedule<TState>(TState state, TimeSpan dueTime, Func<IScheduler, TState, IDisposable> action)
+        {
+            if (action == null)
+                throw new ArgumentNullException("action");
+
+            var dt = Scheduler.Normalize(dueTime);
+            if (dt.Ticks == 0)
+                return Schedule(state, action);
+
+            var d = new MultipleAssignmentDisposable();
+
+            var timer = new System.Windows.Threading.DispatcherTimer(
+#if HAS_DISPATCHER_PRIORITY
+                _priority, _dispatcher
+#elif DESKTOPCLR40 // BACKWARDS COMPATIBILITY with v1.x
+                System.Windows.Threading.DispatcherPriority.Background, _dispatcher
+#endif
+            );
+
+            timer.Tick += (s, e) =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    try
+                    {
+                        d.Disposable = action(this, state);
+                    }
+                    finally
+                    {
+                        t.Stop();
+                        action = null;
+                    }
+                }
+            };
+
+            timer.Interval = dt;
+            timer.Start();
+
+            d.Disposable = Disposable.Create(() =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    t.Stop();
+                    action = (_, __) => Disposable.Empty;
+                }
+            });
+
+            return d;
+        }
+
+        /// <summary>
+        /// Schedules a periodic piece of work on the dispatcher, using a <see cref="System.Windows.Threading.DispatcherTimer"/> object.
+        /// </summary>
+        /// <typeparam name="TState">The type of the state passed to the scheduled action.</typeparam>
+        /// <param name="state">Initial state passed to the action upon the first iteration.</param>
+        /// <param name="period">Period for running the work periodically.</param>
+        /// <param name="action">Action to be executed, potentially updating the state.</param>
+        /// <returns>The disposable object used to cancel the scheduled recurring action (best effort).</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="action"/> is null.</exception>
+        /// <exception cref="ArgumentOutOfRangeException"><paramref name="period"/> is less than TimeSpan.Zero.</exception>
+        public IDisposable SchedulePeriodic<TState>(TState state, TimeSpan period, Func<TState, TState> action)
+        {
+            if (period < TimeSpan.Zero)
+                throw new ArgumentOutOfRangeException("period");
+            if (action == null)
+                throw new ArgumentNullException("action");
+
+            var timer = new System.Windows.Threading.DispatcherTimer(
+#if HAS_DISPATCHER_PRIORITY
+                _priority, _dispatcher
+#elif DESKTOPCLR40 // BACKWARDS COMPATIBILITY with v1.x
+                System.Windows.Threading.DispatcherPriority.Background, _dispatcher
+#endif
+            );
+
+            var state1 = state;
+
+            timer.Tick += (s, e) =>
+            {
+                state1 = action(state1);
+            };
+
+            timer.Interval = period;
+            timer.Start();
+
+            return Disposable.Create(() =>
+            {
+                var t = Interlocked.Exchange(ref timer, null);
+                if (t != null)
+                {
+                    t.Stop();
+                    action = _ => _;
+                }
+            });
+        }
+    }
+}
+#endif

external/rx/Rx/NET/Source/System.Reactive.Windows.Threading/Reactive/Internal/Constants.cs

@@ -0,0 +1,13 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+namespace System.Reactive
+{
+    // We can't make those based on the Strings_WindowsThreading.resx file, because the ObsoleteAttribute needs a compile-time constant.
+
+    static class Constants_WindowsThreading
+    {
+#if !WINDOWS
+        public const string OBSOLETE_INSTANCE_PROPERTY = "Use the Current property to retrieve the DispatcherScheduler instance for the current thread's Dispatcher object. See http://go.microsoft.com/fwlink/?LinkID=260866 for more information.";
+#endif
+    }
+}

external/rx/Rx/NET/Source/System.Reactive.Windows.Threading/Reactive/Linq/CoreDispatcherObservable.cs

@@ -0,0 +1,258 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#if WINDOWS
+using System.Reactive.Concurrency;
+using Windows.UI.Core;
+using Windows.UI.Xaml;
+
+namespace System.Reactive.Linq
+{
+    /// <summary>
+    /// Provides a set of extension methods for scheduling actions performed through observable sequences on UI dispatchers.
+    /// </summary>
+    public static class DispatcherObservable
+    {
+        #region ObserveOn[Dispatcher]
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the specified dispatcher.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcher">Dispatcher whose associated message loop is used to notify observers on.</param>
+        /// <returns>The source sequence whose observations happen on the specified dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcher"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, CoreDispatcher dispatcher)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            return Synchronization.ObserveOn(source, new CoreDispatcherScheduler(dispatcher));
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the specified dispatcher.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcher">Dispatcher whose associated message loop is used to notify observers on.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose observations happen on the specified dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcher"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, CoreDispatcher dispatcher, CoreDispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            return Synchronization.ObserveOn(source, new CoreDispatcherScheduler(dispatcher, priority));
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dependencyObject">Object to get the dispatcher from.</param>
+        /// <returns>The source sequence whose observations happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dependencyObject"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, DependencyObject dependencyObject)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dependencyObject == null)
+                throw new ArgumentNullException("dependencyObject");
+
+            return Synchronization.ObserveOn(source, new CoreDispatcherScheduler(dependencyObject.Dispatcher));
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dependencyObject">Object to get the dispatcher from.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose observations happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dependencyObject"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, DependencyObject dependencyObject, CoreDispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dependencyObject == null)
+                throw new ArgumentNullException("dependencyObject");
+
+            return Synchronization.ObserveOn(source, new CoreDispatcherScheduler(dependencyObject.Dispatcher, priority));
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the current window.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <returns>The source sequence whose observations happen on the current window's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
+        public static IObservable<TSource> ObserveOnDispatcher<TSource>(this IObservable<TSource> source)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+            return Synchronization.ObserveOn(source, CoreDispatcherScheduler.Current);
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the current window.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose observations happen on the current window's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
+        public static IObservable<TSource> ObserveOnDispatcher<TSource>(this IObservable<TSource> source, CoreDispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+            return Synchronization.ObserveOn(source, new CoreDispatcherScheduler(CoreDispatcherScheduler.Current.Dispatcher, priority));
+        }
+
+        #endregion
+
+        #region SubscribeOn[Dispatcher]
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the specified dispatcher.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcher">Dispatcher whose associated message loop is used to perform subscription and unsubscription actions on.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcher"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the specified dispatcher.
+        /// In order to invoke observer callbacks on the specified dispatcher, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, CoreDispatcher)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, CoreDispatcher dispatcher)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            return Synchronization.SubscribeOn(source, new CoreDispatcherScheduler(dispatcher));
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the specified dispatcher.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcher">Dispatcher whose associated message loop is used to perform subscription and unsubscription actions on.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcher"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the specified dispatcher.
+        /// In order to invoke observer callbacks on the specified dispatcher, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, CoreDispatcher, CoreDispatcherPriority)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, CoreDispatcher dispatcher, CoreDispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            return Synchronization.SubscribeOn(source, new CoreDispatcherScheduler(dispatcher, priority));
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dependencyObject">Object to get the dispatcher from.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dependencyObject"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the specified object.
+        /// In order to invoke observer callbacks on the dispatcher associated with the specified object, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, DependencyObject)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, DependencyObject dependencyObject)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dependencyObject == null)
+                throw new ArgumentNullException("dependencyObject");
+
+            return Synchronization.SubscribeOn(source, new CoreDispatcherScheduler(dependencyObject.Dispatcher));
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dependencyObject">Object to get the dispatcher from.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dependencyObject"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the specified object.
+        /// In order to invoke observer callbacks on the dispatcher associated with the specified object, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, DependencyObject, CoreDispatcherPriority)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, DependencyObject dependencyObject, CoreDispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dependencyObject == null)
+                throw new ArgumentNullException("dependencyObject");
+
+            return Synchronization.SubscribeOn(source, new CoreDispatcherScheduler(dependencyObject.Dispatcher, priority));
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the current window.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the current window's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the current window.
+        /// In order to invoke observer callbacks on the dispatcher associated with the current window, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOnDispatcher{TSource}(IObservable{TSource})"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOnDispatcher<TSource>(this IObservable<TSource> source)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+            return Synchronization.SubscribeOn(source, CoreDispatcherScheduler.Current);
+        }
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the current window.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the current window's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the current window.
+        /// In order to invoke observer callbacks on the dispatcher associated with the current window, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOnDispatcher{TSource}(IObservable{TSource}, CoreDispatcherPriority)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOnDispatcher<TSource>(this IObservable<TSource> source, CoreDispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+            return Synchronization.SubscribeOn(source, new CoreDispatcherScheduler(CoreDispatcherScheduler.Current.Dispatcher, priority));
+        }
+
+        #endregion
+    }
+}
+#endif

external/rx/Rx/NET/Source/System.Reactive.Windows.Threading/Reactive/Linq/DispatcherObservable.cs

@@ -0,0 +1,390 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#if !WINDOWS
+using System.Reactive.Concurrency;
+using System.Windows;
+using System.Windows.Threading;
+
+namespace System.Reactive.Linq
+{
+    /// <summary>
+    /// Provides a set of extension methods for scheduling actions performed through observable sequences on UI dispatchers.
+    /// </summary>
+    public static class DispatcherObservable
+    {
+        #region ObserveOn[Dispatcher]
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the specified dispatcher.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcher">Dispatcher whose associated message loop is used to to notify observers on.</param>
+        /// <returns>The source sequence whose observations happen on the specified dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcher"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, Dispatcher dispatcher)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            return ObserveOn_<TSource>(source, dispatcher);
+        }
+
+#if HAS_DISPATCHER_PRIORITY
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the specified dispatcher.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcher">Dispatcher whose associated message loop is used to to notify observers on.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose observations happen on the specified dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcher"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, Dispatcher dispatcher, DispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            return ObserveOn_<TSource>(source, dispatcher, priority);
+        }
+#endif
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the specified dispatcher scheduler.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="scheduler">Dispatcher scheduler to notify observers on.</param>
+        /// <returns>The source sequence whose observations happen on the specified dispatcher scheduler.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="scheduler"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, DispatcherScheduler scheduler)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (scheduler == null)
+                throw new ArgumentNullException("scheduler");
+
+#if HAS_DISPATCHER_PRIORITY
+            return ObserveOn_<TSource>(source, scheduler.Dispatcher, scheduler.Priority);
+#else
+            return ObserveOn_<TSource>(source, scheduler.Dispatcher);
+#endif
+        }
+
+#if USE_SL_DISPATCHER
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dependencyObject">Object to get the dispatcher from.</param>
+        /// <returns>The source sequence whose observations happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dependencyObject"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, DependencyObject dependencyObject)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dependencyObject == null)
+                throw new ArgumentNullException("dependencyObject");
+
+            return ObserveOn_<TSource>(source, dependencyObject.Dispatcher);
+        }
+#else
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcherObject">Object to get the dispatcher from.</param>
+        /// <returns>The source sequence whose observations happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcherObject"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, DispatcherObject dispatcherObject)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcherObject == null)
+                throw new ArgumentNullException("dispatcherObject");
+
+            return ObserveOn_<TSource>(source, dispatcherObject.Dispatcher);
+        }
+#endif
+
+#if HAS_DISPATCHER_PRIORITY
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcherObject">Object to get the dispatcher from.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose observations happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcherObject"/> is null.</exception>
+        public static IObservable<TSource> ObserveOn<TSource>(this IObservable<TSource> source, DispatcherObject dispatcherObject, DispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcherObject == null)
+                throw new ArgumentNullException("dispatcherObject");
+
+            return ObserveOn_<TSource>(source, dispatcherObject.Dispatcher, priority);
+        }
+#endif
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the current thread.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <returns>The source sequence whose observations happen on the current thread's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
+        public static IObservable<TSource> ObserveOnDispatcher<TSource>(this IObservable<TSource> source)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+#if USE_SL_DISPATCHER
+            return ObserveOn_<TSource>(source, System.Windows.Deployment.Current.Dispatcher);
+#else
+            return ObserveOn_<TSource>(source, DispatcherScheduler.Current.Dispatcher);
+#endif
+        }
+
+#if HAS_DISPATCHER_PRIORITY
+        /// <summary>
+        /// Wraps the source sequence in order to run its observer callbacks on the dispatcher associated with the current thread.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose observations happen on the current thread's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
+        public static IObservable<TSource> ObserveOnDispatcher<TSource>(this IObservable<TSource> source, DispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+            return ObserveOn_<TSource>(source, DispatcherScheduler.Current.Dispatcher, priority);
+        }
+
+        private static IObservable<TSource> ObserveOn_<TSource>(IObservable<TSource> source, Dispatcher dispatcher, DispatcherPriority priority)
+        {
+            return Synchronization.ObserveOn(source, new DispatcherSynchronizationContext(dispatcher, priority));
+        }
+#endif
+
+        private static IObservable<TSource> ObserveOn_<TSource>(IObservable<TSource> source, Dispatcher dispatcher)
+        {
+            return Synchronization.ObserveOn(source, new DispatcherSynchronizationContext(dispatcher));
+        }
+
+        #endregion
+
+        #region SubscribeOn[Dispatcher]
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the specified dispatcher.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcher">Dispatcher whose associated message loop is used to to perform subscription and unsubscription actions on.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcher"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the specified dispatcher.
+        /// In order to invoke observer callbacks on the specified dispatcher, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, Dispatcher)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, Dispatcher dispatcher)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            return SubscribeOn_<TSource>(source, dispatcher);
+        }
+
+#if HAS_DISPATCHER_PRIORITY
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the specified dispatcher.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcher">Dispatcher whose associated message loop is used to to perform subscription and unsubscription actions on.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcher"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the specified dispatcher.
+        /// In order to invoke observer callbacks on the specified dispatcher, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, Dispatcher, DispatcherPriority)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, Dispatcher dispatcher, DispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcher == null)
+                throw new ArgumentNullException("dispatcher");
+
+            return SubscribeOn_<TSource>(source, dispatcher, priority);
+        }
+#endif
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the specified dispatcher scheduler.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="scheduler">Dispatcher scheduler to perform subscription and unsubscription actions on.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified dispatcher scheduler.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="scheduler"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the specified scheduler.
+        /// In order to invoke observer callbacks on the specified scheduler, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, DispatcherScheduler)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, DispatcherScheduler scheduler)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (scheduler == null)
+                throw new ArgumentNullException("scheduler");
+
+#if HAS_DISPATCHER_PRIORITY
+            return SubscribeOn_<TSource>(source, scheduler.Dispatcher, scheduler.Priority);
+#else
+            return SubscribeOn_<TSource>(source, scheduler.Dispatcher);
+#endif
+        }
+
+#if USE_SL_DISPATCHER
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dependencyObject">Object to get the dispatcher from.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dependencyObject"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the specified object.
+        /// In order to invoke observer callbacks on the dispatcher associated with the specified object, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, DependencyObject)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, DependencyObject dependencyObject)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dependencyObject == null)
+                throw new ArgumentNullException("dependencyObject");
+
+            return SubscribeOn_<TSource>(source, dependencyObject.Dispatcher);
+        }
+#else
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcherObject">Object to get the dispatcher from.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcherObject"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the specified object.
+        /// In order to invoke observer callbacks on the dispatcher associated with the specified object, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, DispatcherObject)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, DispatcherObject dispatcherObject)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcherObject == null)
+                throw new ArgumentNullException("dispatcherObject");
+
+            return SubscribeOn_<TSource>(source, dispatcherObject.Dispatcher);
+        }
+#endif
+
+#if HAS_DISPATCHER_PRIORITY
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the specified object.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="dispatcherObject">Object to get the dispatcher from.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the specified object's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="dispatcherObject"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the specified object.
+        /// In order to invoke observer callbacks on the dispatcher associated with the specified object, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOn{TSource}(IObservable{TSource}, DispatcherObject, DispatcherPriority)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOn<TSource>(this IObservable<TSource> source, DispatcherObject dispatcherObject, DispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (dispatcherObject == null)
+                throw new ArgumentNullException("dispatcherObject");
+
+            return SubscribeOn_<TSource>(source, dispatcherObject.Dispatcher, priority);
+        }
+#endif
+
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the current thread.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <returns>The source sequence whose subscriptions and unsubscriptions happen on the current thread's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the current thread.
+        /// In order to invoke observer callbacks on the dispatcher associated with the current thread, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOnDispatcher{TSource}(IObservable{TSource})"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOnDispatcher<TSource>(this IObservable<TSource> source)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+#if USE_SL_DISPATCHER
+            return SubscribeOn_<TSource>(source, System.Windows.Deployment.Current.Dispatcher);
+#else
+            return SubscribeOn_<TSource>(source, DispatcherScheduler.Current.Dispatcher);
+#endif
+        }
+
+#if HAS_DISPATCHER_PRIORITY
+        /// <summary>
+        /// Wraps the source sequence in order to run its subscription and unsubscription logic on the dispatcher associated with the current thread.
+        /// </summary>
+        /// <typeparam name="TSource">The type of the elements in the source sequence.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="priority">Priority to schedule work items at.</param>
+        /// <returns>The source sequence whose observations happen on the current thread's dispatcher.</returns>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> is null.</exception>
+        /// <remarks>
+        /// Only the side-effects of subscribing to the source sequence and disposing subscriptions to the source sequence are run on the dispatcher associated with the current thread.
+        /// In order to invoke observer callbacks on the dispatcher associated with the current thread, e.g. to render results in a control, use <see cref="DispatcherObservable.ObserveOnDispatcher{TSource}(IObservable{TSource}, DispatcherPriority)"/>.
+        /// </remarks>
+        public static IObservable<TSource> SubscribeOnDispatcher<TSource>(this IObservable<TSource> source, DispatcherPriority priority)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+            return SubscribeOn_<TSource>(source, DispatcherScheduler.Current.Dispatcher, priority);
+        }
+
+        private static IObservable<TSource> SubscribeOn_<TSource>(IObservable<TSource> source, Dispatcher dispatcher, DispatcherPriority priority)
+        {
+            return Synchronization.SubscribeOn(source, new DispatcherSynchronizationContext(dispatcher, priority));
+        }
+#endif
+
+        private static IObservable<TSource> SubscribeOn_<TSource>(IObservable<TSource> source, Dispatcher dispatcher)
+        {
+            return Synchronization.SubscribeOn(source, new DispatcherSynchronizationContext(dispatcher));
+        }
+
+        #endregion
+    }
+}
+#endif